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NOx

About: NOx is a research topic. Over the lifetime, 26367 publications have been published within this topic receiving 496555 citations.


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Journal ArticleDOI
TL;DR: In this paper, a global three-dimensional model for tropospheric O3-NOx-hydrocarbon chemistry is presented and evaluated with surface, ozonesonde, and aircraft measurements.
Abstract: Results from a global three-dimensional model for tropospheric O3-NOx-hydrocarbon chemistry are presented and evaluated with surface, ozonesonde, and aircraft measurements. Seasonal variations and regional distributions of ozone, NO, peroxyacetylnitrate (PAN), CO, ethane, acetone, and H2O2 are examined. The model reproduces observed NO and PAN concentrations to within a factor of 2 for a wide range of tropospheric regions including the upper troposphere but tends to overestimate HNO3 concentrations in the remote troposphere (sometimes several fold). This discrepancy implies a missing sink for HNO3 that does not lead to rapid recycling of NOx; only in the upper troposphere over the tropical South Atlantic would a fast conversion of HNO3 to NOx improve the model simulation for NOx. Observed concentrations of acetone are reproduced in the model by including a large biogenic source (15 Tg C yr−1), which accounts for 40% of the estimated global source of acetone (37 Tg C yr−1). Concentrations of H2O2 in various regions of the troposphere are simulated usually to within a factor of 2, providing a test for HOx chemistry in the model. The model reproduces well the observed concentrations and seasonal variations of ozone in the troposphere, with some exceptions including an underestimate of the vertical gradient across the tropical trade wind inversion. A global budget analysis in the model indicates that the supply and loss of tropospheric ozone are dominated by photochemistry within the troposphere and that NOx. emitted in the southern hemisphere is twice as efficient at producing ozone as NOx emitted in the northern hemisphere.

312 citations

Journal ArticleDOI
01 Mar 2012-Fuel
TL;DR: In this article, an experimental study was conducted in a port fuel-injection, spark-ignition engine fuelled with blends of gasoline and n-butanol at different spark timings and EGR rates.

310 citations

Journal ArticleDOI
TL;DR: Emphasis is placed on the structure-performance relationship with an aim to design an ideal zeolite-based catalyst for the effective elimination of harmful N-containing compounds.
Abstract: In this review we focus on the catalytic removal of a series of N-containing exhaust gases with various valences, including nitriles (HCN, CH3CN, and C2H3CN), ammonia (NH3), nitrous oxide (N2O), and nitric oxides (NOx), which can cause some serious environmental problems, such as acid rain, haze weather, global warming, and even death. The zeolite catalysts with high internal surface areas, uniform pore systems, considerable ion-exchange capabilities, and satisfactory thermal stabilities are herein addressed for the corresponding depollution processes. The sources and toxicities of these pollutants are introduced. The important physicochemical properties of zeolite catalysts, including shape selectivity, surface area, acidity, and redox ability, are described in detail. The catalytic combustion of nitriles and ammonia, the direct catalytic decomposition of N2O, and the selective catalytic reduction and direct catalytic decomposition of NO are systematically discussed, involving the catalytic behaviors as ...

308 citations

Journal ArticleDOI
01 May 2019-Energy
TL;DR: In this paper, the combined effect of nano additives, combustion chamber geometry and injection timing in a single cylinder diesel engine fuelled with ternary fuel (diesel-biodiesel-ethanol) blends is investigated.

307 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20241
20231,699
20223,249
20211,405
20201,353
20191,367